Related ideas:
-Explosive Guard Posts, Proximity mines, etc
The ESG in OP2 just plain looks wierd.  I'm sure I'm not the only one who thinks this.  It doesn't even look like a weapon.  This idea would affect gameplay in no way whatsoever - but I want a cooler looking ESG turret!  The mines too - the little blinky things are just kinda wierd looking, and don't resemble mines at all.
Now for the part that effects gameplay - the fact that it makes a solid block of mines is kinda wierd too.  Suppose it fired fewer mines, that scattered out randomly over a larger area.  Also they might last longer, and you might lower the ROF a bit.  I hate how the ESG has to be on-site to keep a minefield in place, making removing said minefield a simple matter - kill the ESG, and you're free to go.  Perhaps make a way to kill the mines, as well, with a minesweeper unit/weapon?